The function of Ensembl gene identifier ENSG00000147050 (KDM6A, lysine demethylase 6A) is as follows. Histone demethylase that specifically demethylates 'Lys-27' of histone H3, thereby playing a central role in histone code (PubMed:17713478, PubMed:17761849, PubMed:17851529). Demethylates trimethylated and dimethylated but not monomethylated H3 'Lys-27' (PubMed:17713478, PubMed:17761849, PubMed:17851529). Plays a central role in regulation of posterior development, by regulating HOX gene expression (PubMed:17851529). Demethylation of 'Lys-27' of histone H3 is concomitant with methylation of 'Lys-4' of histone H3, and regulates the recruitment of the PRC1 complex and monoubiquitination of histone H2A (PubMed:17761849). Plays a demethylase-independent role in chromatin remodeling to regulate T-box family member-dependent gene expression (By similarity). {ECO:0000250|UniProtKB:O70546, ECO:0000269|PubMed:17713478, ECO:0000269|PubMed:17761849, ECO:0000269|PubMed:17851529, ECO:0000269|PubMed:18003914}.